JP4426538B2 - Rotary joint - Google Patents

Description

  The present invention relates to a rotary joint that is mounted on various machines and is suitable for supplying a liquid such as a coolant to a rotating shaft side.

  In the conventional rotary joint, a seal ring is attached to the opposing end surfaces of the floating sheet (fixed shaft) and the rotor shaft (rotary shaft) each having a flow path at the shaft center, and the floating sheet is prevented from rotating. The first annular groove formed on the inner peripheral surface of the sliding support hole or the outer peripheral surface of the floating sheet is fixed to the state and slidably provided along the sliding support hole formed in the casing. An O-ring that slides and seals between the inner peripheral surface of the sliding support hole and the outer peripheral surface of the floating sheet is accommodated, and the floating sheet is slid in the rotor axial direction by the fluid pressure supplied to the flow path on the floating sheet side. Thus, the seal portion is formed by bringing the annular seal surfaces of both seal rings into close contact with each other (see, for example, Patent Document 1).

When supplying coolant for cutting to a rotary tool or the like attached to the spindle tip of a machine tool, a rotary joint is directly connected to the spindle rear end or the rotor spindle rear end of the direct-coupled spindle motor. The coolant is pumped from the rotary joint through a flow path provided at the shaft center.
Japanese Patent Laid-Open No. 9-152077

  In particular, in a rotary joint used to supply coolant fluid for cutting to a rotary tool or the like attached to the spindle end of a machine tool, the smooth operation of the floating sheet must be maintained to reduce coolant fluid leakage. Don't be.

  However, as a result of being used in the actual market, the cause of leakage problems is that chips (foreign matter) enter the O-ring part that seals between the floating sheet and the sliding support hole, or the O-ring. In many cases, the coolant liquid that has penetrated into the portion is sludged and solidified to hinder the operation of the floating sheet and lead to leakage.

  The present invention has been made to solve the conventional problems as described above, and its purpose is to prevent foreign matter from entering between the floating sheet (fixed shaft) and the sliding support hole. Accordingly, an object of the present invention is to provide a rotary joint capable of preventing the occurrence of a leakage defect due to a malfunction of the floating seat.

In order to solve the above-mentioned problems, in the rotary joint according to claim 1, a seal ring is attached to each of the opposed end surfaces of the fixed shaft and the rotating shaft each having a flow path at the shaft center, and the fixed shaft rotates. And is slidably provided along a sliding support hole formed in the casing, and is formed on the inner peripheral surface of the sliding support hole or the outer peripheral surface of the fixed shaft. One annular groove accommodates an O-ring that slides and seals between the inner peripheral surface of the sliding support hole and the outer peripheral surface of the fixed shaft, and the fixed by the fluid pressure supplied to the fixed shaft side flow path. a rotary joint configured to seal portions are formed by by sliding shaft in the rotation axis direction are brought into close contact with each other annular sealing surface of the two seal rings, the rotation from the first annular groove At a position away from the axis A second annular groove is formed on the inner peripheral surface of the sliding support hole that always faces the outer peripheral surface of the fixed shaft, and a supply hole that can supply a filling material is formed in the casing. The supply hole is closed in a state in which the first annular groove is filled with the filler in the second annular groove and via the second annular groove from the supply hole, and the supply hole is compressed in the middle of the supply hole. it was a means, characterized in piston normally biased in a direction to push the grease to the second annular groove in the coil spring is al provided.

Rotary joint according to claim 2, wherein, in the rotary joint according to claim 1, wherein the supply hole is a means which is characterized in that it is openably closed by a lid.

Rotary joint according to claim 3, wherein the rotary joint at the rotary joint according to claim 1 or 2, characterized in that the grease is used as the filler.

A rotary joint according to a fourth aspect is the rotary joint according to any one of the first to third aspects, wherein the rotary shaft is connected to a rotary shaft of a machine tool.

In the rotary joint according to claim 1, as described above, the second annular groove is formed on the inner peripheral surface of the sliding support hole that always faces the outer peripheral surface of the fixed shaft at a position farther from the rotation shaft than the first annular groove. The supply hole is formed in the casing so as to be able to supply the filling material into the second annular groove, and the supply hole is closed in a state where the filling material is filled into the second annular hole from the supply hole. By doing so, it is possible to prevent foreign matter from entering between the fixed shaft and the sliding support hole by the filler.

Therefore, it is possible to prevent the occurrence of leakage problems due to malfunction of the fixed shaft.
In addition, since the piston that constantly biases the grease in the direction of pushing the grease into the second annular groove by the compression coil spring is provided in the middle of the supply hole, the amount reduced by the biasing force of the compression coil spring Since the grease is replenished in the second annular groove, an additional effect that the number of periodic grease replenishments can be reduced is obtained.

In the rotary joint according to claim 2, as described above, the supply hole can be opened and closed by the lid so that the lid can be periodically opened to replenish the filling material. It becomes like this.

In the rotary joint according to claim 3, as described above, since grease is used as the filler, the resistance to the coolant is excellent, so that the holding of the filler (grease) is improved, and thereby, periodic This makes it possible to reduce the number of replenishment (grease) filling.

In the rotary joint according to claim 4, as described above, the rotating shaft is connected to the rotating shaft of the machine tool, thereby preventing the machining portion from being adversely affected by the occurrence of a leakage failure due to the malfunction of the fixed shaft. The effect of being able to do it is acquired.

  Embodiments of the present invention will be described below with reference to the drawings.

In the first embodiment, the case where the rotary shaft of the rotary joint is connected to the rotary shaft of the machine tool and coolant (liquid) is supplied as fluid pressure to the machining portion will be described as an example.

FIG. 1 is a sectional view showing the rotary joint of the first embodiment.
The rotary joint according to the first embodiment mainly includes a casing 1, a floating sheet (fixed shaft) 2, a rotor shaft (rotary shaft) 3 of a main shaft motor, a seal portion 4, and foreign matter intrusion prevention means 5. As prepared.

  More specifically, the floating sheet 2 and the rotor shaft 3 are coaxially opposed to each other, and a flow path for supplying a coolant liquid or the like supplied from a supply unit to a machine tool or the like in the axial center portion thereof. A supply hole (fixed shaft side flow path) 2a and a supply hole (rotary shaft side flow path) 3a are formed respectively.

  A sliding support hole 11 for supporting the shaft portion 21 of the floating sheet 2 so as to be slidable in the axial direction is formed in the shaft center portion of the casing 1, and the sliding support hole 11 communicates with a supply portion for a coolant liquid or the like. It has become a state.

  A first annular groove 2 b is formed in the sliding support hole 11, and the first annular groove 2 b slides between the outer peripheral surface of the shaft portion 21 and the inner peripheral surface of the sliding support hole 11 in the floating sheet 2. An O-ring 12 for dynamic sealing is attached.

  The fluid pressure such as the coolant liquid supplied from the supply unit is received by the end surface of the shaft portion 21 to press and slide the floating sheet 2 in the direction of the rotor shaft 3 so that the supply hole 2a and the supply hole 3a communicate with each other. It is supposed to let you.

  A second annular groove 2c is formed on the inner peripheral surface of the sliding support hole 11 that always faces the outer peripheral surface of the shaft portion 21 at a position farther from the rotor shaft 3 than the first annular groove 2b. In the second annular groove 2c, a supply hole 2d capable of supplying the grease G is formed, and the opening of the supply hole 2d is screwed into the second annular hole 2c filled with the grease G from the supply hole 2d. The lid body 13 is closed so as to be freely opened and closed.

  That is, the two annular grooves 2c, the supply hole 2d, the lid body 13, and the grease G constitute the foreign matter intrusion prevention means 5. In Example 1, as the grease G, for example, a grease excellent in water resistance and chemical resistance such as fluorine-based grease is used.

  The seal portion 4 includes a seal ring 41 fixed to the end surface of the floating sheet 2 and a seal ring 42 fixed to the end surface of the rotor shaft 3, and the seal portions 41 and 42 are arranged in a state of facing each other. ing.

  Further, a flange portion 22 is formed on the outer periphery of the end portion of the shaft portion 21 on the seal ring 41 side in the floating sheet 2, and through holes 22 a are formed at two locations on the flange 22.

  The through-hole 22a serves to prevent the floating sheet 2 from rotating, and the anti-rotation pin 23 penetrated through the through-hole 22a is screwed into the screw hole 14 formed in the casing 1 so that the floating sheet 2 The detent of 2 is performed.

  Next, operations and effects of the first embodiment of the present invention will be described.

  In the rotary joint of the first embodiment, as described above, the sliding support hole 11 that always faces the outer peripheral surface of the shaft portion 21 at a position farther from the rotor shaft 3 than the first annular groove 2b in which the O-ring 12 is mounted. A second annular groove 2c is formed in the inner peripheral surface of the casing 2 and a supply hole 2d capable of supplying the grease G is formed in the second annular groove 2c in the casing 1, and the second annular hole 2c is formed from the supply hole 2d. With the grease G filled in, the opening of the supply hole 2d is closed by the screw-type lid 13 so that it can be opened and closed. It becomes possible to prevent the intrusion of foreign matter between them, thereby obtaining the effect that it is possible to prevent the occurrence of leakage problems due to the malfunction of the floating sheet 2.

  In addition, by adopting a configuration in which the opening screw-in type lid 13 of the supply hole 2d is opened and closed, the lid 13 can be periodically opened to replenish the grease G.

  In addition, the use of fluorine-based grease with excellent water resistance and chemical resistance as the grease G filled in the second annular groove 2c improves the holding of the grease G, and thereby the number of times of regular grease G replenishment Can be reduced.

  Further, since the rotor shaft 3 is connected to the rotating shaft of the machine tool, it is possible to prevent the machining portion from being adversely affected by the occurrence of a leakage failure due to the malfunction of the floating sheet 2. It is done.

  Next, another embodiment of the present invention will be described. In addition, about the other Example, illustration and description of the component similar to the said Example 1 are abbreviate | omitted, the same code | symbol is attached | subjected, the description is abbreviate | omitted, and only a different point is demonstrated.

The rotary joint of the second embodiment corresponds to the invention described in claims 1 to 4 .
As shown in the sectional view of FIG. 2, the rotary joint of the second embodiment is always attached in the direction in which the grease G is pushed into the second annular groove 2c by the compression coil spring (supply means) 6 in the middle of the supply hole 2d. The point provided with the urging piston 7 is different from the first embodiment.

  Therefore, in the second embodiment, in addition to the same effect as the first embodiment, the amount of grease G reduced by the urging force of the compression coil spring 6 is replenished into the second annular groove 2c. An additional effect is achieved in that the number of times grease G is replenished can be reduced.

  The embodiment of the present invention has been described above, but the specific configuration of the present invention is not limited to this embodiment, and the present invention can be applied even if there is a design change or the like without departing from the gist of the present invention. include.

  For example, in the embodiment, an example in which the present invention is applied to a rotary joint portion that supplies coolant in a machine tool has been described. However, the present invention can be applied to all other rotary joint portions.

  Moreover, in the Example, although the rotary joint of the structure where the rotation prevention pin 23 was screwed by the casing 1 side was illustrated, it can apply also to the rotary joint of the structure screwed by the flange 22 side of the floating seat 2. Of course.

  In the embodiment, the opening of the supply hole 2d is closed by the lid 13, but the closing structure is arbitrary.

  In the embodiment, the second annular groove 2c is formed on the inner peripheral surface of the sliding support hole 11 that always faces the outer peripheral surface of the shaft portion 21 at a position farther from the rotor shaft 3 than the first annular groove 2b. The casing 1 is provided with a supply hole 2d capable of supplying the grease G in the second annular groove 2c, and the opening portion of the supply hole 2d is filled with the grease G from the supply hole 2d into the second annular hole 2c. However, the supply hole 2d that can supply the grease G is formed in the first annular groove 2b without providing the second annular groove. May be.

  In the second embodiment, the case where the compression coil spring 6 is used as the replenishing means for automatically replenishing the grease to the O-ring portion is exemplified. However, in addition, the gas is supplied by the control means using the gas pressure or the pump pressure. May be controlled.

  Further, an openable / closable valve is provided between the replenishing means and the second annular groove 2c, and the valve is normally closed to prevent the grease that has received the coolant from flowing back to the supplying means side. Good. As this valve, in addition to a manual opening / closing valve, an electromagnetic valve capable of automatic opening / closing can be used.

1 is a cross-sectional view showing a rotary joint of Example 1. FIG. FIG. 6 is a cross-sectional view showing a rotary joint of Example 2.

Explanation of symbols

G grease (filler)
DESCRIPTION OF SYMBOLS 1 Casing 11 Sliding support hole 12 O-ring 13 Cover body 14 Screw hole 2 Floating sheet (fixed shaft)
2a Supply hole (fixed shaft side flow path)
2b First annular groove 2c Second annular groove 2d Supply hole 21 Shaft portion 22 Flange portion 22a Through hole 23 Non-rotating pin 3 Rotor shaft (rotary shaft) of main shaft motor
3a Supply hole (rotating shaft side flow path)
4 Seal part 41 Seal ring 42 Seal ring 5 Foreign matter intrusion prevention means 6 Compression coil spring (supply means)
7 Piston

Claims (4)

A seal ring is mounted on each of the opposed end surfaces of the fixed shaft and the rotating shaft each having a flow path at the shaft center, and the fixed shaft is fixed in a state in which rotation is prevented and is formed on the casing. The first annular groove provided on the inner peripheral surface of the sliding support hole or the outer peripheral surface of the fixed shaft is provided slidably along the support hole, and the inner peripheral surface of the sliding support hole and the fixed An O-ring that slides and seals with the outer peripheral surface of the shaft is accommodated, and the fixed shaft is slid in the direction of the rotating shaft by the fluid pressure supplied to the fixed-shaft side channel, and the annular seals of the two seal rings A rotary joint configured to form a seal portion by bringing surfaces into close contact with each other,
A second annular groove is formed on the inner peripheral surface of the sliding support hole that always faces the outer peripheral surface of the fixed shaft at a position farther from the rotating shaft than the first annular groove, and the second annular groove is formed in the casing. A supply hole capable of supplying a filling material is formed in the groove, and the filling material is filled from the supply hole into the first annular groove through the second annular groove and the second annular groove. A rotary joint characterized in that a supply hole is closed, and a piston that constantly urges grease in a direction in which grease is pushed into the second annular groove by a compression coil spring is provided in the middle of the supply hole . The rotary joint according to claim 1, wherein the supply hole is closed by a lid so as to be freely opened and closed. In the rotary joint according to claim 1 or 2, the rotary joint, wherein the grease is found using as the filler. The rotary joint according to any one of claims 1 to 3, wherein the rotary shaft is connected to a rotary shaft of a machine tool .

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